Rectifier



May 1932. E, KOBEL Tib RECTIFIER Filed Feb' 28, 195o Z0 /f/ Ven/off Patented May 17, 1932 UNITED STATES PATENT OFFICE ERNST KOBEL, OF ENNETBADEN, SWITZERLAND, ASSIGNOR TO AKTIENGESELLSCHAFT SWITZERLAND, A JOINT-STOCK COMPANY OF BROWN BOVERI & CIE., OF BADEN, SWITZERLAND v Application liled February 28, 1930, Serial No. 432,034, and in Germany March 7,

This invention relates to improvementsin electric power rectifying devices of the metallic vapour type in which an electric arc iiows from an anode to a cathode through a body of material vapourized from the cathode by the arc, and moreparticularly to means decreasing the vapour density in the operating chamber or space between the ,l anode and the cathode of such devices.

The arc in an electric power rectifying device is at a high temperature which vapourizes large quantities of the material from the cathode of the device which cathode is Y usually a liquid metal such as mercury. The

. ture itself.

large amount of vapour created produces a high vapour density in the operating space due to which some of the vapour may condense on the anode of the device thereby Yforming a so-called cathode spot which per- VThe 'danger of the production of cathode spot may be largely eliminated if means are provided inthe rectifier for decreasing the amount of material vapourized from the cathode thereby decreasing the vapour density in the operating chamber. Various oo oling systems and cooling devices arranged 1nteriorly on the rectier'have been proposed but none of the devices proposed completely -attain the desired end, mainly the reduction of the amount of material vapourized from the cathode by the arc. In the operation of an electric current rectifying device of the character described, the electric arc moves or wanders over the surface of the cathode,

and it has been found that, if such movement or wandering is restricted, the amount of vapour produced from the cathode is materia-lly` diminished, thereby diminishing the vapour density in the operating spaceof the rectier and largely eliminating the danger wall Zand the closure plate RECTIFIER of the production of cathode spots and the danger ofback-res It is, therefore, among the objects of the present invention to provide an electric power rectifying device in which the amount and range of movement of the electric arc is largely restricted thereby preventing the production of an excessive within the device. l

Another object of the present invention is to produce an electric current rectifying structure in which the area face exposed to the action of is controlled in dependence on the amount of current flowing through the structure.'

Objects and advantages, other than those above set forth, will be apparent romthe Jfollowing description and the drawings, wherein:

Figure 1 is a central elevational view in section showing an embodiment of my in# vention, and

F ig. 2 is a diagrammatic View of circuits and apparatus embodying my invention.

Referring more particularly to the drawings by characters of reference, the reference numeral l indicates a portion of the bottom of a rectifier container or tank constructed in the usual manner and having an aperture therethrough, which vaperture is surrounded exteriorly cylindrical wall 2 of insulating material closed by a plate 3. A water jacket 4 of any suitable construction is attached tothe bottom of the cathode closure plate 3,' for the purpose of providing a pathl for a cooling liuid supplied and discharged through the conduits 6 and 7 connectedtherewith.

rA member 8 of insulating andrefractorymateriahsuch as quartz, substantially in the shape of a truncated cone is the cathode well formed by the insulating 3, in such manner that the open smaller base of the conical member extends into the mercury 9 forming the conductive portion of the cathode. The member 8 may also be formedof any electrical conducting material which does not amalgamate,V with the cathode material 3.. The mercury normally extends into the coneamount of vapour of cathode sur-r the electric arc of the tank 1 by a substantially arranged withiny A coil 16 surrounds the container 12 andi is connectedto a portion of the rectifying circuit (not shoWn)` for apurpose to b'e herein# after described. l

Referring `to the circuit arrangement shown-in Eig. 2,.,it'rwillbe seen that by virtue offconnection ofcoil4 16 acrossfthe shunt 22,

.aportionof the currentowingin the Work Y circuit5 including the secondary windings ofV transformer 17, conductor 18, translating device'.19,.conduct`or 20, shunt 21, conductor 22 and cathode closure plate 3, is diverted through coil 16 and partially energizes the saine. y

As the amount of current increases and the intensity ofthe arc increases-Withinthe rectier,- the. current flowing through the coil 16 increases so that the coil is more highly energized thereby, partially, atleast, attracting the. float. or pistonmember 13.y Increase of? the currentY-oontinues-to increase the energization of the coil until the coil has yattracted .or drawnthe lfloat 13 downward .sufliciently1 to displace `an amount of' mercury propor tionate to the amount of currentfiowing, in the' circuit. Thev amountof mercury cathode surfaceexposed is, therefore, directlyypro-y portional tothe current flowing; throughy the circuit,yvhich is'further directly proportional to,- theintensity of the arc and to the amountpf metallic vapour. produced'thereby.

It will be seeny thatthe structure of the presentl invention controls theamount of mercuryl cathode surface exposed in direct dependence on Ithe amount of currenty iioW- ing. through this circuit. Thel electric arc ioyving ,in the rectifying dev-iceis accordinglyprevented from'movingorWandering over anrextensivesurface of mercur-ythereby reducing-v the quantity ofmetallic vapour created and diminishing. the vapour` density Withinthe'operating'space It Willbe understoodlthatthev coil 16 may fbeconnected Withanyi desired portion of the alternating current supply circuit or'tlie'direct current circuit desired, and that the area of cathode surfaceexposed tothe action of the arcmay thus 'be' controlled by the' current values in any-portionof the installation. The dynamic pressure ofthe' positive mercury'ions, as Well as the reactive pressure of the mercury vapour may, therefore, be balanced or controlled by variation of the mercury level in the container 12.

Although but one embodiment of the present invention has been illustrated, it will be understood that various changes may be made. therein Without departing-.Ig from the spirit of; the invention i. or from tlie i scope of the appended claims.

The invention claimed is 1i. Iln an electriolourrent rectify-in@ devi 75 of'the metallic vapourl type; af metallic'A tank having an aperture throughv theabottomfportion thereof, a Well adapted to receive a liquid cathode material associated with the aperturein saidt'anlt, meansv associated With said. Well for defining` the sur-face areal. of

cathode material exposed` to the. interior-1v of.

said tank, and? means for` controlling the area'of exposed cathode materialv in. depende enceV on.V the flow of.;current,through7 th'e. device..

2.- In an electric, current. rectifying; device.N

of the metallic vapourl type,. a. metallic tank. having an` aperture. through y the I.bottom .pore tion. thereof, a Well. adapted'tofreceive. a l,liq-

uid cathodeinaterialassociatedi with: the api-- ertureinisaid tank, meansarranged interiorly ofsaid .Wells for. dening the surfacearea. of. cathode material exposed, and. means" ar.- ranged eXterior-ly-,ofsaidlWell for control; ling theareaof-.exposed cathode material'iin. dependencev onA the .flow ofk current.` through? the. device.

Y 3. In. an i electric vcur-rentAA rectifying. device'- ofthe metallic vapour typeha metallictanl... having l.an aperture throughmhebottom .pore tion thereof, a` Well. adaptedto receive: a.y lid-A` uidcathode material. associated Withthe ap? erture in; said tank, means iformedj. ofrefracfV tory non-amalgamatlng,V materialiy arrangedinteriorly of. said: Wellf fork defining lthe sur.-

face area ofcathodematerial? eXposedtothe;V interior. of said.tanlr,.andY means arranged`V eXteriorly of`said Welland connectedthere*v With for controllingthe-area of exposedicathode mat'erialindependence on: tlieow ofy current' through the rectjiffyingt device..v

4.. In an electric current: rectifying device.

ofthe metallic vapour type, ametallicqtank.,

having. anv aperture through :thebottom portion thereof, aWelLadaptedto. receive aliqr uidf cathodelnaterialfl associated ywith, theap.- erture; in said tank, a. substantially conicalV member arranged]v Within said` .Well to ieXtend into the cathode material`.therein,.to. dehe. the surface area. thereof, and'. means. associatedand'1 connected With. said. Well forrai'ss,

ing. and lowering.D the catliodemateriall lcvel in responsetothe arc current intherectiy? ingy device.V

tion thereof,l a Well adapted.torecei'vealiqT uid cathodeI material'. associatedwitli" the. ap

i A5. In an electric` current.reetifyingdevice.l

of thefmetallic vapour ty,pe,f.a.metal1ic.tanl`c having7 an aperture.'throughthebottom: por.- c

ERNST KOBEL. 

